nsq源码阅读 nsqlookupd源码五 http.go http_server.go

再来看看关于HTTP的处理逻辑：

httpServer := newHTTPServer(ctx)

新建HTTP实例，跟踪代码，nsqlookupd/http.go：

package nsqlookupd

import (
	"fmt"
	"net/http"
	"net/http/pprof"
	"sync/atomic"

	"github.com/julienschmidt/httprouter"
	"github.com/nsqio/nsq/internal/http_api"
	"github.com/nsqio/nsq/internal/protocol"
	"github.com/nsqio/nsq/internal/version"
)

type httpServer struct {
	ctx    *Context
	router http.Handler
}

//新建httpServer实例
func newHTTPServer(ctx *Context) *httpServer {
	log := http_api.Log(ctx.nsqlookupd.opts.Logger)

	router := httprouter.New()
	router.HandleMethodNotAllowed = true
	router.PanicHandler = http_api.LogPanicHandler(ctx.nsqlookupd.opts.Logger)
	router.NotFound = http_api.LogNotFoundHandler(ctx.nsqlookupd.opts.Logger)
	router.MethodNotAllowed = http_api.LogMethodNotAllowedHandler(ctx.nsqlookupd.opts.Logger)
	s := &httpServer{
		ctx:    ctx,
		router: router,
	}

	//监听路由
	router.Handle("GET", "/ping", http_api.Decorate(s.pingHandler, log, http_api.PlainText))
	router.Handle("GET", "/info", http_api.Decorate(s.doInfo, log, http_api.V1))

	// v1 negotiate
	router.Handle("GET", "/debug", http_api.Decorate(s.doDebug, log, http_api.V1))
	router.Handle("GET", "/lookup", http_api.Decorate(s.doLookup, log, http_api.V1))
	router.Handle("GET", "/topics", http_api.Decorate(s.doTopics, log, http_api.V1))
	router.Handle("GET", "/channels", http_api.Decorate(s.doChannels, log, http_api.V1))
	router.Handle("GET", "/nodes", http_api.Decorate(s.doNodes, log, http_api.V1))

	// only v1
	router.Handle("POST", "/topic/create", http_api.Decorate(s.doCreateTopic, log, http_api.V1))
	router.Handle("POST", "/topic/delete", http_api.Decorate(s.doDeleteTopic, log, http_api.V1))
	router.Handle("POST", "/channel/create", http_api.Decorate(s.doCreateChannel, log, http_api.V1))
	router.Handle("POST", "/channel/delete", http_api.Decorate(s.doDeleteChannel, log, http_api.V1))
	router.Handle("POST", "/topic/tombstone", http_api.Decorate(s.doTombstoneTopicProducer, log, http_api.V1))

	// debug
	router.HandlerFunc("GET", "/debug/pprof", pprof.Index)
	router.HandlerFunc("GET", "/debug/pprof/cmdline", pprof.Cmdline)
	router.HandlerFunc("GET", "/debug/pprof/symbol", pprof.Symbol)
	router.HandlerFunc("POST", "/debug/pprof/symbol", pprof.Symbol)
	router.HandlerFunc("GET", "/debug/pprof/profile", pprof.Profile)
	router.Handler("GET", "/debug/pprof/heap", pprof.Handler("heap"))
	router.Handler("GET", "/debug/pprof/goroutine", pprof.Handler("goroutine"))
	router.Handler("GET", "/debug/pprof/block", pprof.Handler("block"))
	router.Handler("GET", "/debug/pprof/threadcreate", pprof.Handler("threadcreate"))

	return s
}

func (s *httpServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	s.router.ServeHTTP(w, req)
}

//GET /ping
func (s *httpServer) pingHandler(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	return "OK", nil
}

//GET /info
func (s *httpServer) doInfo(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {

	/**
	 *相当于:
	 * type version struct {
	 * 	Version string `json:"version"`
	 * }
	 * v := &version {
	 *	Version: version.Binary,
	 * }
	 * return v, nil
	 */
	return struct {
		Version string `json:"version"`
	}{
		Version: version.Binary,
	}, nil
}

//获取所有topic
//GET /topics
func (s *httpServer) doTopics(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	//获取所有topic的名称
	//详情见nsqlookupd/registration_db.go文件中Registrations相关
	topics := s.ctx.nsqlookupd.DB.FindRegistrations("topic", "*", "").Keys()
	return map[string]interface{}{
		"topics": topics,
	}, nil
}

//获取指定topic下的所有channel
//GET /channels
//@param topic - the topic to list channels for
func (s *httpServer) doChannels(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	topicName, err := reqParams.Get("topic")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_TOPIC"}
	}

	channels := s.ctx.nsqlookupd.DB.FindRegistrations("channel", topicName, "*").SubKeys()
	return map[string]interface{}{
		"channels": channels,
	}, nil
}


//获取指定topic下的所有有效producer
//GET /lookup
//@param topic - the topic to list producers for
func (s *httpServer) doLookup(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	topicName, err := reqParams.Get("topic")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_TOPIC"}
	}

	//topic不存在
	registration := s.ctx.nsqlookupd.DB.FindRegistrations("topic", topicName, "")
	if len(registration) == 0 {
		return nil, http_api.Err{404, "TOPIC_NOT_FOUND"}
	}

	channels := s.ctx.nsqlookupd.DB.FindRegistrations("channel", topicName, "*").SubKeys()
	producers := s.ctx.nsqlookupd.DB.FindProducers("topic", topicName, "")
	//过滤出有效producer
	//详情可查看nsqlookupd/registration_db.go中Producers的FilterByActive()方法
	//和nsqlookupd/options.go中的一些默认配置值
	producers = producers.FilterByActive(s.ctx.nsqlookupd.opts.InactiveProducerTimeout,
		s.ctx.nsqlookupd.opts.TombstoneLifetime)
	return map[string]interface{}{
		"channels":  channels,
		"producers": producers.PeerInfo(),
	}, nil
}

//POST /topic/create
//@param topic - the topic to created
func (s *httpServer) doCreateTopic(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	topicName, err := reqParams.Get("topic")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_TOPIC"}
	}

	//验证topic名称是否合法
	if !protocol.IsValidTopicName(topicName) {
		return nil, http_api.Err{400, "INVALID_ARG_TOPIC"}
	}

	s.ctx.nsqlookupd.logf("DB: adding topic(%s)", topicName)
	key := Registration{"topic", topicName, ""}
	s.ctx.nsqlookupd.DB.AddRegistration(key)

	return nil, nil
}

//POST /topic/delete
//@param topic - the existing topic to delete
func (s *httpServer) doDeleteTopic(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	topicName, err := reqParams.Get("topic")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_TOPIC"}
	}

	//先删除topic下的channel
	registrations := s.ctx.nsqlookupd.DB.FindRegistrations("channel", topicName, "*")
	for _, registration := range registrations {
		s.ctx.nsqlookupd.logf("DB: removing channel(%s) from topic(%s)", registration.SubKey, topicName)
		s.ctx.nsqlookupd.DB.RemoveRegistration(registration)
	}

	//删除topic
	registrations = s.ctx.nsqlookupd.DB.FindRegistrations("topic", topicName, "")
	for _, registration := range registrations {
		s.ctx.nsqlookupd.logf("DB: removing topic(%s)", topicName)
		s.ctx.nsqlookupd.DB.RemoveRegistration(registration)
	}

	return nil, nil
}

//POST /topic/tombstone
//官方解释Tombstones a specific producer of an existing topic
//详情见http://nsq.io/components/nsqlookupd.html#deletion_tombstones
//个人理解为逻辑删除指定topic的一个节点(producer)
//@param topic - the existing topic
//@param node - the producer (nsqd) to tombstone (identified by <broadcast_address>:<http_port>)
func (s *httpServer) doTombstoneTopicProducer(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	topicName, err := reqParams.Get("topic")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_TOPIC"}
	}

	//node格式 <broadcast_address>:<http_port>
	node, err := reqParams.Get("node")
	if err != nil {
		return nil, http_api.Err{400, "MISSING_ARG_NODE"}
	}

	s.ctx.nsqlookupd.logf("DB: setting tombstone for producer@%s of topic(%s)", node, topicName)
	//根据topic查producer
	producers := s.ctx.nsqlookupd.DB.FindProducers("topic", topicName, "")
	for _, p := range producers {
		thisNode := fmt.Sprintf("%s:%d", p.peerInfo.BroadcastAddress, p.peerInfo.HTTPPort)
		//逻辑删除
		if thisNode == node {
			p.Tombstone()
		}
	}

	return nil, nil
}

//POST /channel/create
//创建topic和channel
//@param topic - the topic to created
//@param channel - the channel to created
func (s *httpServer) doCreateChannel(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	//获取topic和channel，并验证是否是有效参数
	topicName, channelName, err := http_api.GetTopicChannelArgs(reqParams)
	if err != nil {
		return nil, http_api.Err{400, err.Error()}
	}

	//新增channel
	s.ctx.nsqlookupd.logf("DB: adding channel(%s) in topic(%s)", channelName, topicName)
	key := Registration{"channel", topicName, channelName}
	s.ctx.nsqlookupd.DB.AddRegistration(key)

	//新增topic
	s.ctx.nsqlookupd.logf("DB: adding topic(%s)", topicName)
	key = Registration{"topic", topicName, ""}
	s.ctx.nsqlookupd.DB.AddRegistration(key)

	return nil, nil
}

//POST /channel/delete
//删除已有topic下的一个channel
//@param topic - the existing topic
//@param channel - the existing channel to delete
func (s *httpServer) doDeleteChannel(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	reqParams, err := http_api.NewReqParams(req)
	if err != nil {
		return nil, http_api.Err{400, "INVALID_REQUEST"}
	}

	//获取topic和channel，并验证是否是有效参数
	topicName, channelName, err := http_api.GetTopicChannelArgs(reqParams)
	if err != nil {
		return nil, http_api.Err{400, err.Error()}
	}

	//验证channel是否存在指定的topic下
	registrations := s.ctx.nsqlookupd.DB.FindRegistrations("channel", topicName, channelName)
	if len(registrations) == 0 {
		return nil, http_api.Err{404, "CHANNEL_NOT_FOUND"}
	}

	s.ctx.nsqlookupd.logf("DB: removing channel(%s) from topic(%s)", channelName, topicName)
	for _, registration := range registrations {
		s.ctx.nsqlookupd.DB.RemoveRegistration(registration)
	}

	return nil, nil
}

//定义节点信息(producer (nsqd))
type node struct {
	RemoteAddress    string   `json:"remote_address"`
	Hostname         string   `json:"hostname"`
	BroadcastAddress string   `json:"broadcast_address"`
	TCPPort          int      `json:"tcp_port"`
	HTTPPort         int      `json:"http_port"`
	Version          string   `json:"version"`
	Tombstones       []bool   `json:"tombstones"`
	Topics           []string `json:"topics"`
}

//GET /nodes
//获取所有已知节点(nsqd)
func (s *httpServer) doNodes(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	// don't filter out tombstoned nodes
	producers := s.ctx.nsqlookupd.DB.FindProducers("client", "", "").FilterByActive(
		s.ctx.nsqlookupd.opts.InactiveProducerTimeout, 0)
	nodes := make([]*node, len(producers))
	for i, p := range producers {
		topics := s.ctx.nsqlookupd.DB.LookupRegistrations(p.peerInfo.id).Filter("topic", "*", "").Keys()

		// for each topic find the producer that matches this peer
		// to add tombstone information
		tombstones := make([]bool, len(topics))
		for j, t := range topics {
			topicProducers := s.ctx.nsqlookupd.DB.FindProducers("topic", t, "")
			for _, tp := range topicProducers {
				if tp.peerInfo == p.peerInfo {
					tombstones[j] = tp.IsTombstoned(s.ctx.nsqlookupd.opts.TombstoneLifetime)
				}
			}
		}

		nodes[i] = &node{
			RemoteAddress:    p.peerInfo.RemoteAddress,
			Hostname:         p.peerInfo.Hostname,
			BroadcastAddress: p.peerInfo.BroadcastAddress,
			TCPPort:          p.peerInfo.TCPPort,
			HTTPPort:         p.peerInfo.HTTPPort,
			Version:          p.peerInfo.Version,
			Tombstones:       tombstones,
			Topics:           topics,
		}
	}

	return map[string]interface{}{
		"producers": nodes,
	}, nil
}

//GET /debug
func (s *httpServer) doDebug(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {
	s.ctx.nsqlookupd.DB.RLock()
	defer s.ctx.nsqlookupd.DB.RUnlock()

	data := make(map[string][]map[string]interface{})
	for r, producers := range s.ctx.nsqlookupd.DB.registrationMap {
		key := r.Category + ":" + r.Key + ":" + r.SubKey
		for _, p := range producers {
			m := map[string]interface{}{
				"id":                p.peerInfo.id,
				"hostname":          p.peerInfo.Hostname,
				"broadcast_address": p.peerInfo.BroadcastAddress,
				"tcp_port":          p.peerInfo.TCPPort,
				"http_port":         p.peerInfo.HTTPPort,
				"version":           p.peerInfo.Version,
				"last_update":       atomic.LoadInt64(&p.peerInfo.lastUpdate),
				"tombstoned":        p.tombstoned,
				"tombstoned_at":     p.tombstonedAt.UnixNano(),
			}
			data[key] = append(data[key], m)
		}
	}

	return data, nil
}

http.go定义了一系列http handle

继续往下可看到：

http_api.Serve(httpListener, httpServer, "HTTP", l.opts.Logger)

创建HTTP server，代码位于internal/http_api/http_server.go里：

package http_api

import (
	"fmt"
	"log"
	"net"
	"net/http"
	"strings"

	"github.com/nsqio/nsq/internal/app"
)

type logWriter struct {
	app.Logger
}

func (l logWriter) Write(p []byte) (int, error) {
	l.Logger.Output(2, string(p))
	return len(p), nil
}

//创建HTTP Serve，并注册handler，handler在nsqlookupd/http.go中定义
func Serve(listener net.Listener, handler http.Handler, proto string, l app.Logger) {
	l.Output(2, fmt.Sprintf("%s: listening on %s", proto, listener.Addr()))

	server := &http.Server{
		Handler:  handler,
		ErrorLog: log.New(logWriter{l}, "", 0),
	}
	err := server.Serve(listener)
	// theres no direct way to detect this error because it is not exposed
	if err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
		l.Output(2, fmt.Sprintf("ERROR: http.Serve() - %s", err))
	}

	l.Output(2, fmt.Sprintf("%s: closing %s", proto, listener.Addr()))
}

到这里nsqlookupd模块的代码就看完了，还剩几个小文件就不在这写了。接下来会看nsqd模块的代码。